Below excerpt from CNA _{(www.channelnewsasia.com/news/singapore/everrise-maintenance-fined-water-contamination-waterford-13854128)}

A contractor has been fined S$8,500 for failing to ensure that a licensed plumber was conducting regulated works at a private condominium along Kim Yan Road, causing contamination to water supply… at Waterford Residence.”

Investigations revealed Everrise Maintenance, a local contractor the managing agent had hired for the condo, was tasked to carry out repair work after a crack line measuring approximately 10cm was found on the external surface of a water tank cover during a PUB site inspection. 

“Such repair works are regulated works that should be carried out by a licensed plumber or by workers under the direct supervision of one,” said PUB. Instead of hiring a licensed plumber, Everrise instructed its workers to patch up the crack line without proper instructions.

Not sure if MA selected the lowest quote amongst contractors. Clearly there are certain redlines to cost savings.

Under the Public Utilities Act, causing contamination to water supplied by PUB carries a maximum fine of S$50,000. Failure to ensure that regulated works are carried out by a licensed plumber carries a maximum fine of S$10,000.